Ch. 11 Mandible, TMJ, and Sinuses Flashcards
how much skull rotation (from the lateral skull position) toward the IR is required with an axiolateral oblique projection for demonstrating the mentum region
45 degrees
how much skull rotation (from the lateral skull position) toward the IR is required with an axiolateral oblique projection for demonstrating a general survey of the mandible
10-15 degrees
specifically, where are the frontal sinuses located
between the inner and outer tables of the skull, posterior to the glabella
if the area of interest is the temporomandibular fossae, what should the angle of the CR to the oml be for the AP axial (modified towne) projection to reduce superimposition of the temporomandibular fossae and mastoid portions of the temporal bone
40 degrees caudal
aligning what plane to the IR prevents rotation of either a PA or an AP axial mandible
msp
to avoid angling the CR for the erect PA (axial) caldwell sinus projection, the head should be adjusted so that the oml is how many degrees from horizontal
15 degrees
what device provides inherent collimation during an orthopantomographic procedure
narrow, vertical slit diaphragm
the axiolateral oblique projection of the TMJ is commonly referred to as what
modified law
what specific positioning error has been committed if both sides of the mandible are superimposed with an axiolateral oblique projection
insufficient cephalic CT angle or skull tilt
the frontal sinuses rarely become aerated before what age
6 years
T/F - for a true PA projection of the mandibular body (if this is the area of interest) the AML should be perp to the IR
true
where should the CR exit for a PA axial projection of the mandible
acanthion (at lips for PA projection)
what must be done to prevent the ramus of the mandible from being superimposed over the c-spine with an axiolateral oblique projection of the mandible
extend the chin
which specific aspect of the ethmoid bone contains the ethmoid sinuses
lateral masses of labyrinth
which cranial line is placed parallel to the floor for orthopantomography of the mandible
IOML
where are the petrous ridges on a well-positioned parietoacanthial projection
just below the maxillary sinuses
to demonstrate any possible air or fluid levels within the paranasal sinuses, it is important to do these two things
- perform positions erect
- use a horizontal beam
the oml forms what degree angle with the IR in the parieto-acantial (waters)
37 degrees
if the patient cannot stand for the lateral projection of the paranasal sinuses, the projection should be taken how
horizontal beam
T/F - MRI is the preferred modality to study soft tissue changes and masses within the paranasal sinuses
true
what is the older term for the maxillary sinuses
antrum/antrum of highmore
T/F - most CT studies of the paranasal sinuses do not require the use of contrast media
true
which paranasal sinuses are demonstrated with an smv projection of the paranasal sinuses
sphenoid, ethmoid and maxillary
T/F - the modified law method provides a bilateral and functional study of the TMJ
true
the axiolateral oblique projection of the TMJ requires how much head rotation from lateral
15 degrees
what is the drainage pathway for the paranasal sinuses called
osteomeatal complex
which paranasal sinuses are projected through the oral cavity with the PA axial transoral projection
sphenoid sinuses
what is the name of the passageway between the maxillary sinuses and the middle nasal meatus
infundibulum
how much skull rotation (from the lateral skull position) toward the IR is required with an axiolateral oblique projection for demonstrating the body of the mandible
30 degrees
a patient comes to the radiology department to rule out a possible polyp within the sphenoid sinus. what routine and/or special projection provides the best overall assessment of the paranasal sinuses for this patient
PA transoral projection in addition to routine 4
what CR angle is required for the AP axial projection of the mandible if the ioml is perp to the IR
42 degree caudal
what CR angle is required for the AP axial projection of the mandible if the oml is perp to the IR
35 degrees caudal
what is the max CR angle needed for all of the axiolateral oblique projections
25 degrees cephalic
a radiograph of a PA (Caldwell) projection for paranasal sinuses shows the petrous ridges are projected into the lower half of the orbits and are obscuring the ethmoid sinuses. the tech used a horizontal beam for the projection. the skull was positioned to place oml at a 15 degree angle from horizontal. what positioning modification is needed
head and neck to be extended more to project petrous ridges below ethmoid
where is the CR centered for an AP axial projection of the mandible
1” superior to glabella
which paranasal sinuses are best demonstrated with a PA (caldwell) projection
frontal and anterior ethmoid
T/F - secondary osteomyelitis is often caused by tumor invasion
false
which projection shows an inferosuperior view of sphenoid and ethmoid sinus
smv for sinuses
which single projection for a paranasal sinus routine provides an image of all 4 sinus groups
lateral
list the 4 most commonly performed routine projections for paranasal sinuses
- lateral
- PA caldwell
- parietoacanthial (waters)
- smv
which projection of the mandible projects opposite half of the mandible away from the side of interst
axiolateral oblique
which imaging system provides a single, frontal perspective of the entire mandible
orthopantomography (panoramic tomography)
the axiolateral oblique projection of the TMJ requires what CR angle
15 degree caudal
which group of paranasal sinuses is best demonstrated with a parietoacanthial (waters) projection
maxillary sinuses
a radiograph of a PA transoral projection shows the sphenoid sinus is superimposed over the upper teeth and the nasal cavity. how must the position be modified to avoid this problem during repeat
increase extension of head and neck to project entire sphenoid sinus through oral cavity
which projection of the mandible demonstrates the entire mandible, including the coronoid and condyloid processes
smv
which projection shows all 4 paranasal sinuses demonstrated
lateral
which sinus is projected through the open mouth with a PA axial transoral projection
sphenoid sinus
what position is most often use when performing a CT study of the sinuses
prone
a radiograph of an axiolateral oblique projection of the mandible shows the body of the mandible is severely foreshortened. the body of the mandible is the area of interest, what positioning error led to this outcome
insufficient rotation of the skull toward the IR, skull should be rotated 30 degrees from lateral position
where should the CR exit for both the PA parietoacanthial and PA transoral projections
level of acanthion
how much skull rotation (from the lateral skull position) toward the IR is required with an axiolateral oblique for demonstrating the ramus region
0 degres - true lateral
which cranial positioning line is placed perp to the IR for a PA or PA axial projection of the mandible
oml
which projection shows the best view of maxillary sinuses
parietoacanthial
the axiolateral (schuller) projection for the tmj requires a CR angle of what
25-30 degrees caudal
which positioning line is placed perp to the IR for a parietoacanthial projection
mml
which projection/method of the tmj requires that the skull be kept in a true lateral position
schuller
what type of IR must be used with digital orthopantomography
digital detector/psp plate
what kVp range should be used for paranasal sinus radiography
75-85
T/F - ultrasound exams of the maxillary sinuses to rule out sinusitis are possible
true
which projection shows the sphenoid sinus in oral cavity
PA transoral
what is the one major difference in positioning between parietoacanthial and PA axial transoral projections
mouth is open with transoral
T/F - the mandibular condyles move anteriorly as the mouth is opened
true
which projection shows the best view of frontal and ethmoid sinuses
PA axial caldwell
an infection of the teeth may travel upward and involve what sinus
maxillary
T/F - the PA axial projection of the mandible produces an elongated view of the condyloid processes
true
T/F - the CR should be angled 20-25 degrees caudal for the PA axial projection of the mandible
false - cephalad
which aspect of the mandible is best visualized with an AP axial projection
condyloid process
